DbExpressionBuilder::RefFromKey Method (EntitySet^, DbExpression^)
Creates a new DbRefExpression that encodes a reference to a specific Entity based on key values.
Assembly: System.Data.Entity (in System.Data.Entity.dll)
public: [ExtensionAttribute] static DbRefExpression^ RefFromKey( EntitySet^ entitySet, DbExpression^ keyRow )
Parameters
- entitySet
-
Type:
System.Data.Metadata.Edm::EntitySet^
The Entity set in which the referenced element resides.
- keyRow
-
Type:
System.Data.Common.CommandTrees::DbExpression^
A DbExpression that constructs a record with columns that match (in number, type, and order) the Key properties of the referenced Entity type.
Return Value
Type: System.Data.Common.CommandTrees::DbRefExpression^A new DbRefExpression that references the element with the specified key values in the given Entity set.
| Exception | Condition |
|---|---|
| ArgumentNullException | entitySet or keyRow is null. |
| ArgumentException | keyRow does not have a record result type that matches the key properties of the referenced entity set's entity type. |
keyRow should be an expression that specifies the key values that identify the referenced entity within the given entity set. The result type of keyRow should contain a corresponding column for each key property defined by entitySet's entity type.
Available since 4.5